Residual mail is a term used to refer to postal mail remaining after most of the mail to be delivered has been sorted to delivery order by automated sorting machines. Letters are currently sorted automatically by a variety of known systems such as DBCS (delivery bar code sorter), MLOCR (multi-line optical character reader) and the like. The USPS has recently funded the development of a sorting system for flats (mail pieces between 11½ and 15 inches long, or between 6⅛ and 12 inches high, or between ¼ and ¾ inch thick), which has the aim of accomplishing automated sorting of flats to delivery groups that correspond to the groups created by automated letter sorting machines. However, even with automation of both letter sorting and flats sorting, some mail pieces will still comprise manual mail that must be sorted by hand rather than by a sorting machine.
Such residual mail may include mail for which the address cannot be decoded by Optical Character Recognition (OCR) or bar code scanning, and mail which cannot be machine sorted due to its physical characteristics such as too stiff, irregular shapes, too thin and open folds. Manual casing refers to the process currently carried out by postal carriers wherein mail that has not been presorted to delivery order is manually sorted to a plurality of slots in a sorting case, where each slot represents a delivery destination. The cased mail is then removed from the slots (“pulled down”) and eventually merged with presorted mail. Where flats and letters have each been presorted, the carrier takes mail from three separate stacks, letters, flats and manual mail, when delivering the mail. The time required for the casing operation combined with the need to merge stacks of presorted mail greatly slows down the manual delivery of mail.
Pitney-Boyes PCT publication WO 2006110486 describes a concept of removing multiple feeders from multiple sorters and providing a pathway from each feeder to each sorter enables fewer feeds per mail piece for conventional sorters. This system includes a plurality of feeders, and a plurality of sorters configured to receive and sort the mail pieces from the feeders. The bins are sorted mail stations, and the feeders are feeding stations. Clamps are used for holding the mail pieces during sortation to expedite the proper movement of mail pieces from the feeders to appropriate sorter bins. However, use of mechanical devices such as clamps to hold mail during sorting is likely to prove difficult.
The mail handling system of the present invention has the goal of making it possible to machine-sort residual mail. The system can be used to sort mail pieces of all types from postcards up to large flats. When used in combination with letter and flats sorting processes, the need to merge mail remains, but the manual casing operation can be virtually eliminated. To further reduce merge operations, the system can be used to sort both residual flats and residual letters.